參數(shù)資料
型號(hào): LTC1174IN8
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: High Efficiency Step-Down and Inverting DC/DC Converter
中文描述: 1 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PDIP8
封裝: 0.300 INCH, PLASTIC, DIP-8
文件頁(yè)數(shù): 6/16頁(yè)
文件大?。?/td> 353K
代理商: LTC1174IN8
6
LTC1174
LTC1174-3.3/LTC1174-5
FUU
W
(Pin 1 connection shown for LTC1174-3.3 and LTC1174-5, changes create LTC1174)
+
V
TH2
+
+
V
LIM2
V
LIM1
I
PGM
7
R
SENSE
0.1
RESET
V
TH1
LB
OUT
2
1174 BD
g
m
V
FB
1.25V
REFERENCE
Q
GND 4
5
SW
1
×
V
OUT
(V
FB
)
+
A1
R1*
31.5k
SET
6
V
IN
LB
IN
3
SHUTDOWN
8
C
T
SLEEP
+
A3
A4
A5
V
FB
* R1 = 51k FOR LTC1174-3.3
R1 = 93.5k FOR LTC1174-5
A2
OPERATIOU
The LTC1174 uses a constant off-time architecture to
switch its internal P-channel power MOSFET. The off-time
is set by an internal timing capacitor and the operating
frequency is a function of V
IN
.
The output voltage is set by an internal resistive divider
(LTC1174-3.3 and LTC1174-5) or an external divider re-
turned to V
FB
pin 1 (LTC1174). A voltage comparator A1
compares the divided output voltage to a reference voltage
of 1.25V.
To optimize efficiency, the LTC1174 automatically switches
between continuous and Burst Mode
TM
operation. The volt-
age comparator is the primary control element when the
device is in Burst Mode operation, while the current com-
parator controls the output voltage in continuous mode.
During the switch“ON” time, switch current flows through
the 0.1
sense resistor. When this current reaches the
threshold of the current comparator A2, its output signal will
change state, setting the flip-flop and turning the switch off.
(Refer to Functional Diagram)
Burst Mode
TM
is a trademark of Linear Technology Corporation.
The timing capacitor, C
T
, begins to discharge until its
voltage goes below V
TH1
. Comparator A4 will then trip,
which resets the flip-flop and causes the switch to turn on
again. Also, the timing capacitor is recharged. The inductor
current will again ramp up until the current comparator A2
trips. The cycle then repeats.
When the load is relatively light, the LTC1174 automatically
goes into Burst Mode operation. The current mode loop is
interrupted when the output voltage reaches the desired
regulated value. The hysteretic voltage comparator A1 trips
when V
OUT
is above the desired output voltage, shutting off
the switch and causing the timing capacitor to discharge.
This capacitor discharges past V
TH1
until its voltage drops
below V
TH2
. Comparator A5 then trips and a sleep signal is
generated.
In sleep mode, the LTC1174 is in standby and the load
current is supplied by the output capacitor. All unused
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LTC1174IN8#PBF 功能描述:IC REG BUCK INV ADJ 1A 8DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
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LTC1174IS8#PBF 功能描述:IC REG BUCK INV ADJ 1A 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
LTC1174IS8#TR 功能描述:IC REG BUCK INV ADJ 1A 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
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